The need for detecting and locating physical alterations is known e.g. in manufacturing and monitoring of structures like PCBs (Printed Circuit Boards), semiconductor wafers, fabrics, and security fences. Such structures are exposed to alterations like in-continuities (e.g. cut-offs), random or non-random irregularities, disruptions, bending, or any other physical change in the structure.
According to one known approach, the occurrence of an alteration in a structure is checked with respect to a reference. For example, in the field of printed electronic components, there are known procedures for scanning a surface and comparing the scanned sample to a reference model. Another known approach, suitable for a structure with a predefined design (e.g. wired structure), is to detect that the structure follows the design rules, e.g. the distance between the wires, wire width, permitted radius of curvature.
These methods are not suitable for very long structures such as fences and textiles, because the required reference model is extremely large and thus problems specific to very long surfaces arise, such as the need for large computer memory volumes to store the reference model and strong processors. Likewise, there are structures that are not characterized by precise design rules to which reference can be made to examine a deviation that indicates a change.
There is, accordingly, a need in the art for a system and method for detecting and locating variations and alterations present in long and/or large structures, that will overcome the problems indicated above.